I'm caught in his jet wash!

TXiceman has it right (as do others). I might add, when you feel the suck-in / suck-out motion, hold the wheel steady. One of my previous camper did that sometimes. I found it easiest to stay as far right as possible and let them pass, keep the steering wheel completely steady, don't try to correct. It may feel like it's being pulled in, but it really is not. And third, drive slower. I know this is probably the hardest thing, but if you slow down and let traffic (especially the big trucks) zoom by, the faster they go by, the less you feel the in-out suction. I learned early, with my first TT and Suburban to let them pass as quickly as possible. If you are both within a mile per hour or two apart from each other and the truck or bus, or whatever is creeping beside you, the in-out motion seems to be exaggerated and goes on forever. Rather than battling wits over your speed, just slow down and let them pass quicker. I found this to actually be the best solution (until I got a bigger truck). I don't feel the in-out suction any more with My current TT and truck combination.